Strategies of Improving CsPbX3 Perovskite Quantum Dots Optical Performance

Abstract

All-inorganic perovskite quantum dots (QDs) (CsPbX3, X = Cl, Br, I) become promising candidate materials for the new generation of light-emitting diodes for their narrow emission spectrum, high photoluminescence quantum yield, and adjustable emission wavelength. However, the perovskite QDs materials still face instability against moisture, high-temperature, and UV-light. Many strategies have been reported to improve the photoluminescence (PL) performance of QDs while increasing their stability. These strategies can be divided into three main categories: doping engineering, surface ligand modification, coating strategies. This paper reviews the recent research progress of surface ligands, inorganic and polymer coating, and metal ions doping of CsPbX3 QDs. Partial substitution of Pb2+ with non-toxic or low-toxic metal ions can improve the formation energy of the perovskite lattice and reduce its toxicity. The surface polymer modification can use their ligands to bond with the uncoordinated lead and halogen ions on perovskite QDs surface to reduce surface defects, thereby improving the PL intensity and stability. In addition, the organic or inorganic coating materials on perovskite QDs can effectively avoid their contact with the external environment, thereby improving the stability of the perovskite. The optical properties of the modified QDs, including transient absorption spectra, temperature-dependent PL spectra, time-resolved photoluminescence (TRPL) spectra properties, etc. were discussed to explain the physical mechanism. The potential applications of all-inorganic perovskite QDs as down-conversion fluorescent materials in light-emitting diodes are presented. Finally, we provide some possible methods to further improve the PL performance of the all-inorganic perovskite QDs.

Design rules for obtaining narrow luminescence from semiconductors made in solution

“…On the heels of 3D bulk metal-halide perovskites, solution-processed nanocrystal analogues (MHP nanocrystals) have made a similarly explosive entrance to the field of nanotechnology for conventional and quantum optoelectronics within the last decade. The volume of research activity on MHP nanocrystals prompts us to defer to numerous reviews, all published since 2019, that detail the current states of MHP nanocrystal synthesis, 491,492 characterization, 493 stability, [494][495][496][497] doping, 498 heterostructures, 499 selfassembly, 500 encapsulation, 501 device applications, [502][503][504][505][506][507] and more, [508][509][510][511][512] with a particularly comprehensive review of the MHP nanocrystal state-of-the-art published in 2021. 513 Here, we aim to present the major considerations for achieving bright, efficient, and narrow emission from nanoscale ABX3 structure synthesized in solution.…”

Boosting the stability of lead halide perovskite nanocrystals by metal–organic frameworks and their applications

“…81,85,[87][88][89][90] The majority of polymers have high oxygen diffusion coefficients, which negatively affect the durability and performance of PNCs. 92 However, organic materials don't appear to be the greatest choice for preserving PNCs because of their poor temperature resistance. In general, inorganic matrixes outperform organic ones in terms of strength and thermal sensitivity.…”

Aging Effects on the Exciton Relaxation and Diffusion Processes in CsPbBr3 Nanocrystals

“…In understanding the emission properties of light-emitting materials, investigations of the temperature dependence of photoluminescence (PL) and excitation relaxation dynamics are extremely powerful; they allow us to probe the number of emitting states, their nature (intrinsic or related to defects), coupling with phonons and their energy, and exciton binding energies. [24][25][26][27][28][29] For these reasons, several experiments investigating PL temperature dependence have already been performed with fully inorganic NC films, and particular attention been paid to green-emitting CsPbBr 3 films that, thanks to the high exciton binding energy of about 40 meV, [1,[30][31][32] show efficient excitonic emission up to room temperature. Interestingly, these experiments did not provide a unique and clear picture of the basic photophysics of these NCs.…”

“…In understanding the emission properties of light‐emitting materials, investigations of the temperature dependence of photoluminescence (PL) and excitation relaxation dynamics are extremely powerful; they allow us to probe the number of emitting states, their nature (intrinsic or related to defects), coupling with phonons and their energy, and exciton binding energies. [ 24–29 ]…”